A zoom lens with high optical specification performances and an incorporated electronic imaging system that is much slimmer in its depth direction, albeit having that zoom lens mounted thereon includes a lens group G1 located nearest to the object side, having a reflecting surface M for bending an optical path. The zoom lens satisfies two conditions with respect to a length d as measured along the optical path from the apex of the surface nearest to the object side in lens group G1 to reflecting surface M and a dimension a of the outside shape of a positive lens, found first as viewed along the optical path from the reflecting surface M toward an image side of the zoom lens, in a direction parallel with an optical axis on an object side of the zoom lens with respect to the position where the optical path is bent, respectively.